Oil well drilling and treating fluids

ABSTRACT

THICKENED HYDROCARBON FLUIDS OBTAINED BY THE IN SITU REACTION OF A LONG CHAIN AMINE AND ISOCYANATE TO FORM UREA, AND METHOD OF USE FOR DRILLING FLUIDS, FRACTURING FLUIDS, PACKER FLUIDS, AND THE LIKE IN PETROLEUM PRODUCTION OPERATIONS.

United States Patent 1 3,650,951 Patented Mar. 21, 1972 U.S. Cl. 252-85 6 Claims ABSTRACT OF THE DISCLOSURE Thickened hydrocarbon fluids obtained by the in situ reaction of a long chain amine and isocyanate to form urea, and method of use for drilling fluids, fracturing fluids, packer fluids, and the like in petroleum production operations.

BACKGROUND It has been found desirable in field practice to use thickened hydrocarbon fluids as fracturing fluids, packer fluids, and drilling fluids. Many methods of forming such fluids are known to the art such as the use of soaps of fatty acids. Thickened oil systems are preferred for these uses, however, emulsions of the water-in-oil type, invert emulsions, have been found to be useful for drilling fluids. One serious disadvantage of the fatty acid soap method for thickening is the extensive mixing necessary to formulate the thickened hydrocarbon product. This is particularly undesirable in view of the fact that such compositions are generally formulated in the field where elaborate mixing or shearing equipment is not readily available.

One method used for increasing the flow of fluid through subterranean formations penetrated by the bore of a well involves liquid injection through the well bore into the well formation at hydrostatic pressures high enough to form a passage-way by fracturing the subterranean formation into which the liquid is injected. It can be seen that fractures may be formed by such hydraulic action, but such passage-ways must be held open to permit the desired fluid flow following fracture. The general practice is to convey into the subterranean formation together with the fracturing fluid a particulated material to act as a propping agent to physically hold such fractures open. Propping agents such as sand, aluminum beads, glass beads, walnut shells, and the like have been used. One of the greatest difficulties encountered in the use of fracturing fluids containing propping agents is maintaining the particulated solids suspended somewhat evenly in the liquid media used to hydraulically fracture the formation. A disadvantage of some presently used fracturing fluids, such as the thickened or viscous oils, is that the viscosity changes with temperature. That is, the fluid may be of a satisfactory consistency to maintain the propping material in an even suspension at ground level temperatures, but when subjected to higher temperatures in the well tubing and Well formation, the viscosity is lowered permitting the propping agent to settle out of the fracturing fluid. Further, the storage stability of many presently used fracturing fluids containing propping agents is not satisfactory.

Corrosion of oil well casings has long been recognized as a serious problem in petroleum production. Various types of materials have been utilized to pack the annulus between the casing and the tubing and the annulus between the casing and the surrounding formation to inhibit corrosion. Presently used packer fluids include aqueous base compositions thickened with clays and containing additives such as weighting agents, corrosion inhibitors, and biocides, etc. Caustic is sometimes added to the packer fluid to inhibit the acidification of the packer composition while it is in place. Oil base packer fluids are preferred in view of their natural anti-corrosive properties. Many of the current compositions presently utilized are difiicult to pump into a small annular space when they are sufiiciently thick to evenly suspend additives, and those compositions which are readily pumpable due to to their lower viscosity have the disadvantage of permitting additive materials to settle out and plug the lower end of the annular spaces. Further, it is desirable that the packer fluid be maintained in a state in which it may be readily removed from the annular areas to rework the well. In order to achieve this, a 'thixotropic material is necessary. A review article setting forth desirable properties for packer fluids is Oil Mud Packs for Combating Casing Corrosion, Materials Protection, V. No. 6, June 1966, pp. 21-25. It is also very desirable to have a packer fluid which may be readily formulated at the well site, especially if it can be formulated from the fracturing or drilling fluid used at the same site.

The drilling of oil or gas wells is generally accomplished by a rotary drill having a hollow drill stem with a bit attached to its lower end. During the drilling, a fluid known as a drilling fluid is continuously circulated downward through the drill stem and bit, out against the working face of the hole, and then upwardly to the surface through the annular space between the drill stem and the wall of the bore hole. The drilling fluid serves to cool and lubricate the drill bit, suspend and remove cuttings from the hole, and prevent the flow of liquids or gasses from the formations into the bore by applying a positive pressure to the face of the formation. Both water base and oil base drilling fluids are presently utilized. Oil base or water-in-oil emulsion type fluids are preferred to reduce or prevent swelling of argillaceous materials in underground formations traversed by the well bore, to prevent sloughing when drilling through shale materials, and to prevent vaporization experienced in the use of water base compositions in hot wells. Further, many of the water-clay muds are expensive to maintain in good condition. Drilling fluids may also contain minor proportions of various compositions to impart special properties to the composition, such as wall-building agents, weighting agents, dispersing agents, viscosity modifiers, corrosion inhibitors, etc. Some disadvantages of the presently used drilling fluids include the wide range of viscosities experienced with the normal variations of temperatures encountered in oil well operations, the inability of the generally used oil base systems to tolerate water, and the requirement of special mixing equipment at the oil well site to formulate the drilling fluid from presently used amine reacted clays, etc.

SUMMARY OF THE INVENTION This invention is directed toward a composition and method to obviate many of the disadvantages experienced with prior art materials. This invention provides a composition which may be used as a drilling fluid, packer fluid or fracturing fluid, and which may be readily formulated at the well site without requiring elaborate mixing equipment. The thixotropic hydrocarbon oil base composition of our invention comprises a major proportion of hydrocarbon oil and a minor proportion of urea produced by the in situ reaction of an aliphatic amine and an isocyanate 'selected from the group consisting of aromatic and aliphatic monoand polyisocyanates. Mixtures of amines and monoand polyisocyanates may be used. The amine terminated structure is preferred.

Aliphatic amino compounds are preferred amine reactants, patricularly amines containing an aliphatic group of from about 6 to 22 carbon atoms attached to an amino nitrogen. Such aliphatic groups may be a branched or straight hydrocarbon chain and saturated or unsaturated.

Primary mono-amines selected from the group consisting of N-normal-alkyl, N-normal-alkenyl and N-secondaryalkyl amines having from about 6 to 22 carbon atoms are preferred. N-secondary-alkyl amines are especially useful due to their low melting points resulting in amines having fluid properties under field conditions. One preferred subclass is N-secondary-alkyl amines having from about 7 to 18 carbon atoms. The aliphatic group may be a cyclic group or an arylalkyl group such as 9,10-phenylstearylamine as derived from oleic acid.

-Isocyanates suitable for the process of this invention include those isocyanates which react with an amine to form a urea. Long chain aliphatic isocyanates are suitable wherein the aliphatic group contains from about 6 to 22 carbon atoms. It is preferred to use difunctional isocyanates, or pre-polymers thereof, including diisocyanates such as toluene diisocyanate, hexamethylene diisocyanate, and the long chain aliphatic diisocyan-ates such as derived from aminostearyl amine and aminomethylstearylamine.

Suitable hydrocarbon oils for use in the composition of this invention include crude petroleum, petroleum distillates such as kerosene and fuel oil, residual oils, or a blend of crude and refined oils.

The compositions of this invention may be readily formulated by simple mixing of the amine and isocyanate reactants in the hydrocarbon oil to form urea in situ. It is preferred to add the amine to the oil first and then add the isocyanate with stirring. To form the ureas, it is suitable to use from the stoichiometric requirement of amine and isocyanate to about 40 percent excess of amine. That is, the mole ratio of amine to diisocyanate may range from about 2:1 to 2.8: l.

The compositions of this invention may be formulated in batches by simple mixing in tanks, adding desirable additive agents such as corrosion inhibitors, biocides, propping agents, weighting agents, etc. with stirring and stored for use as desired. Such compositions are stable over wide temperature ranges and over long periods of time.

The compositions of this invention are especially well suited for continuous production such as may be desired in the case of fracturing and drilling fluids. The urea may be formed on a continuous basis in the pipe leading to the well bore by simply introducing the appropriate quantities of amine and isocyanate to the hydrocarbon oil flow in the pipe. Desired additive agents may be introduced toward the well head down line from the introduction of amine and isocyanate so that such agents will be adequately and evenly suspended in the thickened fluid.

Suitable compositions according to this invention may be formulated using from about 0.05 to 2 weight percent urea concentration in the oil. Preferred compounds contain from about 0.1 to 1.0 weight percent urea. The optimum concentration of urea will vary depending upon the type of hydrocarbon utilized and the particular thickening properties desired.

The thickened hydrocarbon compositions of this invention are readily emulsified for use in aqueous systems using conventional emulsifiers and well known emulsion techniques.

Compositions may be formulated according to this invention to a wide range of viscosities to suspend evenly and for long periods of time various suitable additive agents such as weighting materials, propping agents, corrosion inhibitors, biocides, etc., and to maintain even suspension of such materials over wide variations of temperature. Further, the compositions of this invention exhibit desirable thixotropic properties which enables them to be pumped into narrow annular spacings While at the same time furnishing sufficient body to maintain suspension of materials over wide annular spacings when the materials are used as packer fluids. The thixotropic properties of the compounds of this invention also permit packer fluid which has been in place for long periods of time to be readily removed from the casing for remedial work in the well bore. The urea containing compositions of this invention are particularly well suited for use as a packer fluid where the composition remains in the annular space for several years, since the urea will not decompose into undesirable chemicals such as acids, etc. The compounds of this invention are especially useful as drilling fluids and fracturing fluids by virtue of their capability to evenly suspend desirable additives, provide adequate suspension for removal of cuttings and the like, and at the same time not produce deleterious effects to the oil bearing formation. The thickened compositions of this invention also will tolerate relatively large amounts of Water.

One advantage of the composition of this invention is its ease of formulation by simple mixing which may be readily carried out at the well site without the requirement of elaborate equipment. A further advantage is the continuous method of formulation possible directly in the hydrocarbon oil flow to the well head. Still another advantage is the use of one basic thickened oil base fluid which may be adapted for use as a drilling fluid, packer fluid, or fracturing fluid in petroleum operations by the simple addition of desired additives for the particular use.

The following examples are presented to illustrate the present invention.

EXAMPLE I Mid-Continent crude oil was thickened by the in situ reaction of N-sec-alkyl primary amine and toluene diisocyanate. The crude oil was added to a beaker and an amine was added directly to the crude oil with stirring in an amount to produce the concentration and mole ratio noted in Tables I and II, following which toluene diisocyanate was added to produce the concentration and mole ratio noted. The stirring was continued until maximum thickening was obtained, usually a matter of minutes. The viscosity was obtained by measurement with a Brookfield Viscometer at the temperatures and revolutions per minute noted in Tables I and II. Round spindles were used for all viscosity determinations.

TABLE I Brookfield viscosity in centipoises at- 0 F. F. 212 F.

Percent 2 4 10 20 2 4 10 20 2 4 10 20 Amine, additive l cone. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. rpm. N-sec-alkyl (C1-n)-primary amine 1 600 240 240 270 250 175 65 400 350 180 112 3 7,500 4, 000 2,050 1, 050 2, 900 1, 650 870 540 4,000 2, 150 1, 000 580 5 3,000 1, 950 1, 100 760 1, 800 990 480 280 800 400 240 180 1 8, 600 5, 400 2, 900 1, 900 2, 420 2, 450 1,160 610 3, 000 1, 550 704 420 5 Solid gel 17, 600 8, 000 4, 800 2, 400 15,500 7, 400 3, 700 2,000 N-sec'alkyl (GHQ-primary amine 1 6, 200 4, 200 2, 150 1,330 4, 200 2, 325 1,000 600 100 50 40 10 3 5, 100 8, 900 4, 400 2, 680 2, 800 3, 250 1, 540 940 180 60 20 5 19, 400 10, 900 6, 200 3, 100 7, 300 4, 250 2, 040 1, 220 250 180 80 20 1 15, 800 10, 050 5, 550 3, 720 6,000 3, 700 2,050 1, 330 460 240 72 5 Solid gel Solid gel Solid gel N-sec-alkyKOn-u)-primary amine 1 1, 400 1, 050 750 540 150 76 50 10 10 5 5 3 12,000 8, 200 3, 800 2, 640 120 115 80 45 20 20 20 15 5 500 600 500 260 250 100 70 35 40 40 20 1 48, 000 27, 800 14, 500 6, 900 27,000 13,000 5,800 600 40 35 30 24 5 Solid gel 1 Solid gel Solid gel TABLE L-Conti lined Brooklield viscosity in centipoises at 0 F. 75 F. 212 F.

Percent 2 4 20 2 4 10 20 2 4 10 20 Amine, additive 1 cone. r.p.m. 1".p.ni. r.p.m. r.p.ni. r.p.iii. r.p.in. i'.p.ni. i'.p.in. r.p.ni. r.p,m. r.p.ni. r.p.m.

N-see-iilkyl(C eel-primary amine 1 1,000 800 450 310 350 200 120 80 25 18 20 20 .3 6,200 4, 200 2, 100 1, 050 2,100 1, 225 640 430 20 20 20 5 11, 400 8, 200 4, 600 2, 050 5,000 4,000 2. 400 1, 080 5, 400 3,000 1,480 920 1 Solid gel 04, 000 35,000 17,500 11,000 10,400 5, 800 2,500 1, 150

5 Solid gel Solid gel Solid gel Control( No additive) 240 104 220 210 20 15 12. 5 12 10 10 5 5 Amine plus toluene diisoeyanate.

NOTE.-Mo1ar ratio of above amines to diisocyanete is 2:1.

TABLE II Brookfield viscosity in eeiitipoises at 0 F. 75 F. 212 F.

Percent 2 4 10 20 2 4 10 20 2 4 10 20 Amine, additive 1 eoiic. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.rn. r.p.m. r.p.m. r.p.m. r.p.n1. r.p.ni.

N-sec-olky1(C -q) primary amine 1 1,000 800 450 310 400 225 150 100 180 90 00 40 3 2,500 1, 800 1, 150 840 1,000 600 300 200 500 300 100 80 5 8, 300 2, 500 1, 550 1, 100 4, 000 1,000 500 300 1, 800 000 400 150 1 11,600 8,000 4, 050 3, 400 7,000 3, 250 1, 450 750 3,100 1, 520 635 334 5 Solid gel Solid gel Solid gel N sec-alkyl(C )-primary amine 1 6,600 3,200 1, 150 890 2,600 1, 550 800 480 100 00 90 80 3 5, 900 2, 950 900 760 2, 700 1, 880 000 520 120 100 110 75 5 8, 400 5, 800 4, 500 1, 820 6, 600 3, 600 3, 950 2, 320 360 215 110 G6 1 5, 200 3, 400 2, 050 1, 440 4, 200 2, 400 1, 200 740 500 250 180 100 5 Solid gel Solid gel Solid gel N-sec-alkyl(u )-primai'y amine 1 250 300 250 200 200 150 100 G0 40 40 35 3 1, 400 1,000 600 405 500 350 200 130 60 50 50 5 2, 300 1, 750 1, 050 730 1, 100 700 400 280 120 110 80 1 1, 600 1, 100 1, 050 600 1, 000 600 350 240 110 100 55 5 Solid gel Solid gel Solid gel N-see alkyKCia-z )primary amine 1 1,300 1, 150 850 630 150 150 150 145 20 20 15 10 3 12,800 8,000 4, 2, 500 4,000 2,500 1, 200 760 500 480 180 80 .5 Solid gel 5,400 3, 350 2,050 670 850 520 210 1 Solid gel 2,850 3,300 1, 680 1,000 780 480 100 95 5 Solid gel Solid gel Solid gel 1 Amine plus toluene diisocyanate.

NOTE.Molar ratio of above amine to diisoeyanate is 2.4:1.

EXAMPLE II The procedure of Example I was followed using West 45 Texas Crude Oil resulting in the viscosities shown in Tables III and IV.

TABLE IIl.-WES1 TEXAS CRUDE Brookfield viscosity in centipoises 1t- Percent 2 4 10 20 2 4 10 20 2 4 10 20 Amine, additive 1 cone. r.p.in. r.p.m. r.p.ni. r.p.ni. r.p.m. r.p.m. r.p.ni. r.p.m. r.p.m. r.p.m. r.p.in. mini.

N-see-alkyl(C )-priniary amine 1 1,100 1,250 1, 250 1, 250 185 98 160 110 00 20 3 5,200 4, 100 2,750 2,050 350 275 200 166 180 120 70 80 5 3, 800 3, 150 2,300 1, 840 270 190 108 190 110 85 40 1 4,600 3,800 2, 900 2, 350 400 265 150 121 310 200 110 20 5 Solid gel Solid gel Solid gel N-sec-alkyl(C )primary amine 1 18 000 13,500 8, 000 5, 400 385 230 120 74 200 100 55 20 3 38,000 24 000 12 800 8,200 1,500 1,300 1, 1,000 850 210 120 85 5 10, 000 9, 500 6, 000 4, 400 1, 400 0 180 110 60 20 1 30,000 28,000 18, 000 11, 500 2, 300 1, 350 720 450 620 180 75 5 Solid gel Solid gel Solid gel N-sec-alkyl(C )-prin1ary amine 1 12,000 8,000 4, 800 3, 400 2,200 1, 350 740 480 280 110 60 20 3 12, 000 10, 500 6, 000 4, 000 3, 250 2, 050 1, 220 700 480 235 85 65 5 28,000 20,500 12, 400 8, 200 4,300 2,800 1, 560 1,010 900 410 110 80 1 44, 000 29, 000 16,800 10, 850 5, 000 3, 600 1, 900 1, 215 1, 010 840 510 340 5 olid gel Solid gel Solid gel N-sec-alkyl (Clo-2013111115137 amine 12, 000 8, 000 4, 600 3, 140 2, 450 1, 450 810 517 Q0 180 90 55 Solid gel Solid gel Solid gel Solid gel Solid gel Solid gel Control (No additive) 200 170 150 15 20 10 20 10 5 5 5 l Amine plus toluene diisoeyanate.

NOTE.-Molar ratio of above amines to diisocyanate is 2:1.

TABLE IV.WEST TEXAS CRUDE Bi-ookfield viscosity in centipoises at- F 75 F. 212 F.

Percent 2 4 2 4 10 20 2 4 10 20 Amine, additive 1 cone. r.p.m r plm. r pm. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m r.p.m. r.p.m

N-sec-alkyl (C O-primary amine .1 2,500 2, 750 2,800 2, 500 80 80 70 63 20 20 10 10 3 8, 500 7, 000 4, 800 3, 500 370 300 225 182 140 70 2O 5 16,500 12, 500 8, 900 6, 570 1, 170 685 380 252 900 450 100 70 1 25,000 20, 500 14, 200 9, 900 6, 120 3, 300 1, 580 930 1, 500 680 210 95 5 S01 gel Solid gel Solid gel N -scc-alkyl (Co-m)-pr1mary amine 1 3,000 2,700 1,800 1,500 1,500 875 448 280 80 60 40 3 21, 600 16, 500 10, 000 6, 640 7,000 4, 300 2, 228 1, 380 980 410 110 60 5 10,000 7,800 4, 880 3, 600 2, 300 1, 350 720 460 100 90 80 1 24, 400 16, 500 9, 900 6, 900 6,000 3, 485 1, 760 1,070 950 515 95 50 5 Solid gel Solid gel Solid gel N-sec-alkyl (C1i-1i)-primary amine 1 7, 000 5,500 3, 920 3,120 140 160 155 137 40 40 20 1O 3 16,000 12,000 7, 600 5,400 1, 360 940 512 388 50 5O 40 5 30, 000 22, 500 14,000 10, 000 1, 600 1, 020 595 418 90 40 20 10 1 Solid gel Solid gel Solid gel 5 Solid gel Solid gel Solid gel N-sec-alkyl (Owed-Primary amine 1 33,000 28,000 18, 600 14, 400 100 100 100 100 20 20 20 10 3 5,000 6, 000 5, 200 960 80 80 75 20 15 10 10 5 60,000 42,000 23, 600 14, 800 18,000 10, 350 5, 100 3, 120 910 410 200 1 30,000 23, 000 14, S00 10, 640 4, 200 3,000 1, 800 1, 260 850 210 120 70 5 Solid gel Solid gel Solid gel 1 Amine plus toluene diisoeyanate.

N 0TE.Molar ratio of above amines to diisocyanate is 2.4:1.

EXAMPLE III 25 The procedure of Example I was followed using Southern Illinois Crude Oil resulting in the viscosities shown in Tables V and VI.

TABLE V.SO UTHE RN ILLINOIS C R UDE Brookfield viscosity in centipoises at- 0 F 75 F. 212 F.

Percent 2 4 20 4 1O 20 2 4 10 20 Amine, additive 1 cone. r.p.m. r p m r.p m. r.p.m. r.p.m. r.p.m. r.p.m. rlpJn. r.p.m. r.p.m. r.p.m. r.p.m. N-seo-alkyl(C )-p1in1ary amine 1 1, 250 1, 350 1, 1,000 320 205 140 190 120 75 40 3 300 4, 800 2, 540 2, 100 680 340 190 120 310 175 100 85 5 6,800 4, 100 2, 900 1, 180 710 390 195 135 240 230 90 1 7, 500 5, 780 3, 12 2, 050 820 420 225 195 410 290 175 110 5 Sol' e1 Solid gel Solid gel N-sec-alkyKCq-m-primary amine 1 20,050 18, 600 10, 150 6, 180 420 240 160 80 210 170 170 90 3 43,500 27, 800 12, 400 7, 280 1, 600 1,200 1, 650 990 540 265 240 5 42, 100 26, 300 12,200 7,050 1,800 1, 650 1, 100 970 780 560 200 1 49, 400 29, 750 13,400 8, 160 2, 420 1, 750 980 560 1, 100 880 640 240 5 Solid gel Solid gel Solid gel N-see-alkyl(C11-u)-primary amine 1 13, 750 9,400 5, 100 3, 780 2,400 1,700 880 410 270 110 65 1O .3 13, 900 10, 205 e, 000 4, 350 4,100 2,010 1,110 840 510 260 75 25 5 27, 750 20, 100 13, 600 8, 700 4, 620 2,800 1, 605 1, 100 1, 010 780 110 80 1 46, 050 32, 400 18, 700 11, 750 6, 300 4, 200 1, 990 1, 300 1, 120 840 510 345 5 Sohd gel Solid gel Solid gel N-see-alkyl(O15-m)primary amine- 11,600 9, 120 5, 720 3,410 2, 110 1, 120 870 410 309 70 45 1 23, 750 15, 410 8, 600 7,400 3, 900 2, 750 1, 410 901 610 530 215 90 3 46, 500 27, 400 15, 410 9, 700 19, 410 15, 310 6,410 3, 950 10,700 6, 300 2,420 1, 050 .5 Solid gel Solid gel Solid gel Solid gel Solid gel Solid gel Control (No additive) 230 190 170 170 30 20 20 10 10 5 1O 5 1 Amine plus toluene diisocyanate. N oTE.Mola-r ratio of above amines to diisocyanate is 2.421.

TABLE VL-SOUTHERN ILLINOIS CRUDE Brookfield viscosity in centipoises at 0 F. 75 F. 212 F.

Percent 2 4 10 20 2 4 10 20 2 4 10 20 Amine, additive cone. r.p.m. r.p.rn. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. N-sec-alkyl(C -p)-pnmary amines 1 2, 310 2, 420 21100 1, 980 90 95 80 80 10 10 15 10 3 9, 100 7, 200 4, 700 3, 500 410 300 225 170 120 90 85 70 5 18, 750 13,700 9, 700 6, 650 1, 050 780 410 250 770 410 220 115 l 28, 400 20, 300 16, 750 10, 100 5, 400 2, 800 1, 520 990 1, 700 740 395 190 5 S01' gel Solid gel Solid gel N-Sec-alkyMCo-m)-primary amines l 4, 100 2, 800 1,900 1, 360 1, 610 990 410 270 80 65 70 45 3 23, 200 17,000 10, 200 6, 900 6,800 5,200 2,220 1, 410 1, 100 520 120 65 5 23, 400 16,900 10,400 6, 350 2, 100 1, 410 865 490 995 500 140 55 l 27, 200 16, 500 9, 800 6, 870 6, 300 5, 200 1, 940 1,070 950 540 175 40 5 S01 gel Solid gel Solid gel N-secalkyl(Cn-n)-p1imary amines- 1 8, 400 5, 440 8, 750 3,000 150 135 50 45 45 40 3 16, 720 12, 200 7, 880 6, 320 1, 120 970 610 440 75 55 60 60 5 32, 190 24, 320 14, 100 920 1, 240 1, 110 645 410 100 70 45 15 1 Sol d gel Solid gel 3,400 1,800 880 190 5 Solid gel Solid gel Solid gel N-see-alkyl(GHQ-primary amines 1 1, 210 1,105 1, 150 1, 190 190 100 95 30 35 30 4O 3 5, 700 4, 120 2, 100 1, 220 75 85 100 70 20 15 20 10 5 Solid gel Solid gel 3,100 2, 050 990 810 1 Sol d gel Solid gel Solid gel 5 Solid gel Solid gel Solid gel 1 Amine plus toluene diisocyanate.

Nora-Molar ratio of above amines to diisocyanate is 2.4:1.

EXAMPLE IV The procedure of Example I was followed using residual oil (American Oil Company Low Sulphur Indus- VIII.

TABLE VIL-CUTBACK RESIDUAL FUEL OIL Brookfield viscosity in eeiitipoises at- F. 75 F. 212 F.

Percent 2 4 10 20 2 4 1O 20 2 4 10 20 Amine, addmve l cone. r.p.m. r.p.1n. r.p.rn. r.p.m. r.p.rn. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.rn. r.p.1ii.

ontrol 3 35 340 345 100 75 60 50 20 20 10 10 N- ee.alkyl (C S-primary amine .1 4, 3,900 2,800 1,200 1,000 1,100 650 400 60 50 37.5 33 3 22,000 9, 500 8, 700 7, 500 11,600 5, 900 3,400 2, 180 740 470 250 158 5 44,000 31,000 14, 300 9, 200 11, 000 6, 500 3,200 1,800 3,100 1, 650 1,050 854 1 68,050 40, 500 22,400 12, 250 14,60 7,200 3, 400 2,100 12, 400 5, 500 2,600 1, 470 5 Solid gel Sol gel Sol gel N-see-alkyl (Co-)-P mary amine... .1 2,000 2, 500 2,800 1,800 200 200 200 160 60 30 3 62, 500 34, 000 21, 550 11, 400 37,000 21, 000 10, 800 6, 500 8,400 4 300 2, 120 1, 230 5 Solid gel Solid gel 65,000 32,150 14, 700 7, 500 1 Solid gel Solid gel 74,000 41, 000 20, 050 10,100 5 Solid gel Solid gel Solid gel N -sec-a1kyl (Cram-primary amine 1 5,000 4, 750 5, 000 4, 900 1,000 850 600 440 100 100 85 68 3 20,000 18, 500 14, 500 9, 350 1, 100 1, 100 900 760 90 80 75 70 5 28, 000 20, 000 10, 300 5, 700 19, 000 11, 500 5, 800 3,700 3, 200 1, 800 860 530 1 Sol d gel Solid gel Solid gel 5 Solid gel Solid gel Solid gel N-sec-alkvl (Ci5-2o)-prim&ry amine 1 1, 750 1, 500 1, 300 1, 150 200 200 150 120 20 20 15 14 3 3, 500 3, 000 4 2,100 300 280 175 140 40 20 20 5 18,00 13,000 8, 200 5, 700 6, 500 4, 250 2, 400 150 140 120 73 1 Solid gel Solid gel 10, 500 5,400 3, 150 1, 400 5 Solid gel Solid gel Sol gel 1 Amine plus toluene diisocyanate. N0'1E.-Molar ratio of above amines to diisocyanate is 2:1.

TABLE VIIL-CUIBACK RESIDUAL FUEL OIL Brookfield viscosity in ceiitipoises at- 0 F. 75 F. 212 F Percent 2 4 10 20 2 4 I0 20 2 4 10 20 Amine, additive 1 cone. r.p.m. r,p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.'m. r.p.m. r.p.m r.p.m.

Control 3 34 345 1 75 6 20 20 10 10 N- ee-a'lkyl (C yprimary amine .1 6,000 4,750 3, 300 2,850 2,500 1,600 900 650 740 300 190 120 3 12,000 9, 500 6, 000 5, 350 3,900 2,650 1, 550 1,100 2, 420 1, 050 650 420 5 16, 000 12,000 8, 200 6, 400 8, 600 5, 500 3,200 2, 060 3,900 l, 800 880 500 1 Solid gel Solid gel 6, 800 3,200 1,100 850 5 Solid gel Solid gel Solid gel N-seealkyl (Co-1o)-pi'imary amino .1 5,000 3,000 2, 400 1,000 2,000 1,250 800 500 50 3 28 3 16,000 12,000 7, 900 5, 890 5, 200 3,400 1, 900 1, 260 800 485 270 180 5 32, 000 23,000 14, 000 9, 700 11,200 7, 200 4, 400 2, 860 3,400 1, 800 910 500 1 Solid gel Solid gel 8, 400 4,100 2,000 080 5 Solid gel Solid gel Solid gel N-see-alkyl (C11-14)-1)Iimaly amine .1 3,000 2,750 2,400 2,150 400 350 275 220 140 120 55 3 6,000 6,000 4,000 3,100 3,100 2,000 1, 200 800 170 130 T0 5 26, 000 18, 500 11, 800 8, 800 8, 000 5, 400 3, 2, 080 2,200 1, 300 680 400 1 66, 500 42, 800 21, 450 10, 500 18, 900 11,600 5, 900 4, 400 11,500 6,400 3,280 1, 880 5 Solid gel Solid gel Sol" gel N-sec alkyl (Clem-primary amine 1 1, 500 1,625 1,700 1, 775 200 175 100 30 20 15 15 3 9, 500 9,000 8,000 8,400 2,200 1, 500 950 660 40 35 30 24 5 4, 500 5, 000 3, 850 3, 350 2, 800 1, 850 850 740 70 45 25 25 1 Solid gel Solid gel 8, 000 4,400 2, 220 1, 340 5 Solid gel Solid gel Sol gel 1 Amine plus toluene diisocyanate. NOTE.Molar ratio of above amine to diisoeyonate is 44:1.

55 EXAMPLE v The procedure of Example I was followed using Kerosene resulting in the viscosities shown in Tables IX and TABLE IX.KE ROSENE Brookfield viscosity in centipoises at- 0 F. 75 F. 212 F.

Percent 2 4 10 20 2 4 10 20 2 4 10 20 Amine, additive 1 cone. r.p.in. r.p.m. r.p.m. r.p.m. r.p.m .r.p.m .r.p.m. r.p.ni. rpm; r.p.ni. r.p.ni. r.p.in.

N-sec-aik i operimar amines .3 525 407 259 187 1,205 602 320 i07 220 62 37 N-sec-alkyl(Co-io)-primary amines 3 90 82 58 48 70 50 32 24 35 15 12 8 N-sec-alkyl(C )-prlmary amines 3 60 4 27 22 15 17 12 9 N-see-alky1(Ci5 zo)-pr1rnary amines .3 665 347 152 99 2 162 07 50 10 5 5 5 Formed precipitate 1 Amine plus toluene diisoeyanate.

.No'rE.-Molar ratio 01 above amines to diisoeyanate is 2:1.

TAB LE X.KE ROSENE Brooldield viscosity in centipolses at- F. 75 F. 212 F.

Percent 2 4 2 4 10 4 10 20 Amine, additive 1 cone. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m; r.p.m. r.p.m. r.p.m. r.p.m. r.p.m.

N -sec-alky1(C )-prlmary amines 3 20 22 20 20 10 9 10 5 3, 840 2, 750 1, 572 1, 034 2, 705 1, 523 752 467 280 155 76 N-sec-a1ky1(C )-primary amines 3 250 150 86 58 175 95 30 5 1, 270 922 594 431 745 480 277 189 62 33 23 N-sec-alkyl(C )-primary amines 3 230 165 94 66 210 127 68 38 30 10 7 7 5 26, 450 15, 075 7,270 4, 320 13, 450 6, 600 3, 420 2, 245 60 45 40 22 N-seo-a1kyl(C152o)-primary amines 3 110 49 37 10 7. 5 7 5 2. 5 2 2 5 Formed precipitate 1 Amine plus toluene diisoeyanate. Noam-Molar ratio of above amines to diisoeyanate is 2.4;1.

EXAMPLE VI The procedure of Example I was followed using #2 20 fuel oil resulting in the viscosities shown in Tables XI and XII.

TABLE XI.-#2 FUEL OIL Brookfield viscosity in centipoises at 0 F. 75 F. 212 F.

Percent 2 4 10 20 4 10 20 2 4 10 20 Amine, additive l cone. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m.

N-see-alkyl (C )-primary amines 3 800 515 273 173 830 410 221 137 175 115 55 32 5 1, 150 695 366 238 1, 270 695 260 170 180 48 28 N-sec-alkyl(Cn-io)-primary amines 3 470 330 202 149 245 165 99 71 10 15 12 8 5 985 804 560 430 185 150 89 40 20 13 5 N-sec-alkyl (Cling-primary amines 3 290 230 137 98 30 20 17 14 5 1, 390 940 417 265 623 372 202 131 10 5 2. 5 1. 5

N -sec-alkyl (C15-2o)-D1imary amines .3 405 807 203 153 10 15 16 17 5 2.5 7 7 5 3, 340 1, 990 1, 052 796 2, 390 1, 385 717 457 140 105 58 37 1 Amine plus toluene diisooyanate. Norm-Molar ratio of above amine to diisooyanate is 2:1.

TABLE XII.#2 FUEL OIL Brookfield Viscosity in centipoises at 0 F. 75 F. 212 F.

Percent 2 4 10 20 2 4 10 20 2 4 10 2O Amine, additive cone. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m.

N-sec-alkyl (G Q-primary amines .3 440 255 142 97 465 278 136 87 82 40 26 5 990 585 320 203 690 385 188 119 330 180 78 43 N-sec-alkyl (G Q-primary amines .3 443 345 224 165 100 75 43 32 10 5 10 8 5 8, 360 5, 210 2, 680 1, 586 7, 440 4, 470 2, 236 1, 314 265 67 41 N-sec-alkyl (Cu-14)-pr1mary amines .3 5 350 304 268 223 260 192 119 94 25 25 17 15 N-seo-alkyl (GHQ-primary amines 3 445 320 208 453 250 167 97 67 10 5 2 3 5 8, 600 4, 970 2, 548 1, 628 9, 660 5, 030 2, 440 1, 430 264 80 5 4 1 Amine plus toluene diisocyanate. NOTE.Molar ratio of above amine to diisocyanate is 2.4:1.

EXAMPLE VII The procedure of Example I was followed using N- oleyl primary amine and toluene diisocyanate in both kerosene and. #2 fuel oil at the concentration and mole ratios noted in Table XIII. The thickened oil compositions exhibited viscosities set forth in Table XIII.

TABLE XIII I V I Brookfield viscosity in centipoises at- 0 F. 75 F. 212 F.

Percent 2 4 10 20 2 4 10 20 2 4 10 '20 Amine, addltive conc. Ratio Solvent r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m.

N-oleylamine 3 2:1 Kerosene 370 220 109 69 45 25 17 13 30 17. 5 7 6 5 2:1 do- 1, 800 1, 042.5 508 307 1, 120 632. 5 320 194. 5 10 5 2. 5 1. 5 N-oleylamine 3 2. 4:1 Kerosene. 715 408 182 110 230 127. 5 67 43 70 45 22 12 N-oleylamine 3 24:1 2 Fuel (111.- 355 215 122 87 92. 5 46 32 30 15 8 '7 5 2:1 do 2, 105 1, 250 618 376 1, 305 745 368 230 80 60 30 22 Amine plus toluene diisocyanate.

13 EXAMPLE VIII cording to the procedure of Example I using toluene diisocyanate and the amine noted in Table XV. The concentrations and mole ratios are shown in Table XV. Kerosene and water were added to the thickened product TABLE XIV Brookfield viscosity in centipoises at 0 F. 75 F. 212 F.

Percent 2 2 4 10 20 2 4 10 20 Amine, additive; cone. Ratio Solvent r.p.In. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.rn. r.p.m. r.p.m.

' N-see-alkyl-(C -z .i 2:1 Kerosene... 120 90' "4s '35 2s 1s "'15 10 5 "a" 5 primary amine. .3 2: do 605 305 151 93 190 108 68 39 45 28 15 .5 2:1 do 2,670 1,420 646 372 2,185 1,145 509 287 720 340 168 109 N-sec-alkyl-(Cis-20)- .1 2.4:1 Kerosene 3O 25 17 15 20 10 6 8 10 5 0 4 primary amine. .3 2.421 do.. 290 183 94 62 130 42 28 40 15 7 7 .5 2.4:1 do 1,910 1,025 453 257 1,505 805 359 202 430 235 118 73 1 Amine plus dlphenylmethylene 4,4-diisoeyanate.

EXAMPLE IX in the amounts of 5 and 10 percent and the appearance TABLE XV.KEROSENE Was as noted in Table XV.

Dilution with oil Percent Additive cone. Percent Result Percent Result Control (110 additive) 5 No change 5 2 layers. 10 ..d0 10 D0.

1 t 5 Hazy liquid 5 Hazy liquid, 2layers. l 10 ..do 10 Same, H O suspended. N-sec-alkyl (C amine 3 5 H2O suspended.

10 go. 5 0. 10 Do.

1 5 2layors (emulsion). 10 Do. N-SBC-ilikyKCa-m) amine 3 5 Do.

10 H ODo. d d

5 g suspen e 5 i 10 Do.

1 5 2 layers, heavy emulsion. 10 Do. N-seealkyl(Cn-u) amine 3 5 Do.

' 10 H ODo. d d

5 z suspen e i 10 Do.

1 I 5 2layers (emulsion). l 10 Do. N-sec-alkyl(Ci -2o) amine 3 5 Some H2O suspended.

10 1120 suspended.

5 l 5 2 layers (emulsion). l 10 Do.

1 I 5 2 layers (emulsion). 2 1 1(5) 1130. N-sec-alkyl(C amine o. P) i 10 Do.

5 j 5 H2O suspended. l 10 Do.

1 5 2layers (emulsion). 10 o. N-seealkylw -m) amine 3 t 5 H2O suspended.

1 1(5) 30. o. i 10 Do.

1 1 Clear fluid 5 2 layers (emulsion). (C q 12 .do 10 go. N-sec-alkyl 1 amine 5 0. 1 10 10 Do.

5 5 5 H2O suspended. 10 10 D0.

1 5 Clear fluid 5 2 layers (emulsion). l 10 do. 10 Do. N-see-alkyKCu-go) amine Z 3 l 5 Hazy fluid 5 Do. l 10 do 10 D0. 5 5 Clear fluid 5 Do. 10 .d 10 Do.

1 Mole ratio of above amine to diisocyanate is 2:1. 2 Mole ratio of above amine to diisocyanate 1s 2.4:1.

15 EXAMPLE X 16 at the rate of 2 pounds per barrel and N-coco-trimethylenediamine may be added as an effective biocide at the rate 0.5 pound per barrel. Barium sulfate may be added as a weighting agent as necessary.

EXAMPLE XIII Fracturing fluid may be prepared by adding 0.5 pound of N-sec-alkyl(C amine to 1 barrel of #2 fuel oil, and then adding 0.23 pound of toluene diisocyanate with TABLE XVI.-#2 FUEL OIL P t Dilution with oil Dilution with water ercen Additive cone. Percent Result Percent Result Control (no additive)--.-; 5 No g 8 31 5 2 layers 1 5 Clear fluid- 5 H O suspended. d 10 Do. N -sec-alkyl(C )-am1ne l 3 5 Do. 12 B0. 0. i 10 Do.

5 H O suspended. 1 I 10 Do. 3 5 Do. 10 Do. 5 5 Do. 10 Do.

Cloudy fiuid 5 2 layers (emulsion). 10 do 10 Do. N -sec-alkyl(Cu-14) amine 5 Clear fluid 5 Do.

moan- O'INHUIWH N -sec-alkyl (Cg-1o) amine 2 N-sec-alkyhCn-m) amine l N-see-alkyl(Cu-u)aminez N-sec-alkyl(C7- )-amine 1 N -sec-a1kyl(C1 -2 amine 2 7! 50 H "n" "MAM mm "m" "N" Mn" 0 Very viscous Do. 5 H2O suspended.

5 H ODsuspended (emulsion).

o. 5 2 layers (emulsion).

Do. 5 H2O suspended.

5 ZIay erS (emulsion).

6 H 0 suspended. o.

5 H Olguspended (less viscous).

5 2 layggrs (emulsion).

5 H O suspended. 10 D0. 5 Do. 10 Do.

5 2 layers (emulsion). 10 Do. 5 Do.

Some H 0 suspended. 5 H OIsuspended. o.

1 Mole ratio of above amine to diisocyanate is 2:1. 2 Mole ratio of above amine to diisocyanate is 2.4: 1.

EXAMPLE XI Drilling fluid may be prepared by adding 1 pound of N-sec-alkyl(C amine to 1 barrel of residual fuel oil cutback with #2 fuel oil -(6040 percent) followed by the addition of 0.42 pound of toluene diisocyanate and stirring to form urea in situ thereby thickening the oil composition. Following formation of the urea, a weighting agent or other desired additive may be added as desired depending upon well conditions.

EXAMPLE X 11 A packer fluid may be prepared by adding 1.1 pounds of N-sec.alkyl(C amine to 1 barrel of Mid-Continent crude oil followed by the addition of 0.3 pound of toluene diisocyanate with stirring to form urea in situ in the crude oil. Following formation of the urea, N-tallow trimethylenediamine dioleate may be added as a corrosion inhibitor hand stirring to form urea in situ. Eighty-four pounds of Ottawa sand of about 12-20 mesh particles size is added to the thickened oil to serve as a propping agent. The fracturing tfluid containing the propping agent may then be pumped into the well under pressure to effect the fracture of subterranean formations and to maintain the fractured fissures open to the flow of petroleum liquids.

EXAMPLE XIV 3,650,951 17 to drop through 12 inches of the thickened fluid. In especially suitable fracturing fluids, 20 mesh sand will fall less than 1 foot per minute. Table XVII records the rates of fall observed.

18 to 2 weight percent of di-substituted urea produced by the in situ reaction of an unsubstituted aliphatic primary monoamine having about 6 to 22 carbon atoms in a hydrocarbon aliphatic group attached to the amino nitrogen and a TABLE XVII Time for grain of sand to fall one foot at concentrations oi #2 fuel Additive Kerosene oil 1% 3% 5% x 3 seconds Control "i x d 3secIonds T x secon s... 00 viscous..-- 0o viscous. N'sec'alkyl(c7g)amme 1 "i x secongs secongs. Bo.

- x 10 secon s... 20 secon s. o. N 'sec'alkyucimamme 1 "i x 1% secongs". 1g secongs. 11 minute, 19 seconds x 1 secon s..- 1 secon s. 0o viscous.

N'sec'alkyucu'mamme 1 "i x seconds... 10 seconds. 5 minutes. N -sec-alkyl(Ci5-zo)amine 1 E 1%???83}? 1O gf x 5 seconds" 2minutes 30 seconds. -ol yl x 10 d p. N-s c-al yl( r-n "33 g x 5 seconds... 4minutes, Do. N-sec-alkylt o-mamin 2 u x 5 g gf tgg Do.

5 seconds. I N-sec-alkyl(C11 14)amine 2 I; 10 Seconds"' 10 seconds $6 5 33??? Sohd N-sec-alkylwn-zoamin 1 .-{f ifi ifggggfi d o. N'oleylamme 2 10 seconds -do 10 seconds.

1 Molar ratio of above amines to diisocyanates is 2: 1. 2 Molar ratio of above amines to diisocyanates is 2.4: 1.

EXAMPLE XV diisocyanate selected from the group consisting of toluene The sand drop test of Exarnpe XIV was performed in diisocyanate, diphenylmethylene 4,4-diisocyanate and hythe same fashion using diphenylmethylene 4,4diisocyanate drocarbon aliphatic diisocyanates having about 6 to 22 in the noted mole ratios and concentrations instead of carbon atoms in a hydrocarbon group, said diisocyanate toluene diisocyanate, as shown in Table XVIII. reacting with said monoamine to form said disubstituted TABLE XVIII Time for grain of sand to fall one foot at concentrations of No. 2 fuel Additive Kerosene oil .1% 3% .5

N-sec-alkyl(C1-q)amine 1 x 3 seconds 3seccilmds 3 seclgnds.

o--- 0. .do. Do. do. Do. .do. Do. do Do. 5 seconds Too viscous.

do... 5 seconds. N-oleylamine 1 .do. Do. do... Do. N-sec-alky1(C1- )an1ine 2 3 seconds 3 seconds.

do Do. Do. Do. Nsec-alkyl(C11-14)amine 2 X go. o. N -sec-alkyl(C15-zu)amine 2 X T00 viscous o. N oleylamine 2 x Do. it Do.

1 Mo1ar ratio of above amines to diphenylmethylene 4,4-diisocyanate is 2:1. 2 Molar ratio of above amines to diphenylmethylene 4,4-dnsocyanate 1s 2.4:1.

While in the foregoing specification this invention has urea and said amine being added in the mole ratio of been described in relation to certain preferred embodiamine to diisocyanate of from 2:1 to 28:1. ments thereof, and many details have been set forth for 2. The composition of claim 1 wherein said amine is sepurpose of illustration, it will be apparent to those skilled lected from the group consisting of N-normal-alkyl, N- in the art that the invention is susceptible to additional normal-alkenyl, and N-secondary-alkyl amines having embodiments and that certain of the details described from about6to 22 carbon atoms. herein can be varied considerably without departing from 3. The composition of claim 1 wherein said amine is N- the basic principles of the invention. secondary-alkyl amine having from about 7 to 18 carbon We claim: atoms.

1. A thixotropic hydrocarbon oil base composition com- 4. The composition of claim 1 wherein said diisocyanate prising a major portion of hydrocarbon oil and about 0.05 75 is toluene diisocyanate.

19 20 5. The composition of claim 1 wherein from about 0.1 3,232,870 2/1966 Cowan et a1. 2528.5 to 1.0 weight percent in situ formed urea is present. 3,243,372 3/1966 Dreher et a1 260553 X 6. The composition of claim 1 wherein said amine is 3,358,005 12/1967 Garber et a1. 260553 X N-secondary-alkyl amine and said diisocyanate is toluene dii 5 HERBERT B. GUYNN, Primary Examiner References Cited UNITED STATES PATENTS 2,667,457 1/1954 McChrystal 252--8.55

2,925,387 2/1960 Traise et a1 260553 X 10 2528.55; 260553 3,097,168 7/1963 Gibson 2528.55

M. HALPERN, Assistant Examiner 

